A mechanism is required to insert and withdraw a horizontal or vertically mounted pallet with a workpiece into the workzone of a machine tool. Modem machine tools are provided with guard doors to contain coolant and debris formed by the machining operation within the workzone. The guard doors need to be open in order to insert a workpiece into the workzone, and interlocks are provided that prevent the machine from operating before the guard doors are closed. As a result, any mechanism that is used to convey the pallet into the workzone has to be withdrawn from the workzone before the guard doors can close and the machine can operate.